WCF Rest service authentication

Question

Hi, I am trying to write my first WCF Rest service following http://msdn.microsoft.com/en-us/library/ee391967%28v=MSDN.10%29.aspx

Sometimes when I go to websites they ask a user to enter a username and password...

I just wanted to know when Im testing my service with Http Get options in a browser,

Is there a way so that the browser asks for authentication, and also how would the WCF rest service get those authentication details...

Thanks